Add new mastercard bin range
Add new mastercard bin range

Also converted code to use dispatch_once while I was in there.

stripe/stripe-ios,fbernardo/stripe-ios,stripe/stripe-ios,stripe/stripe-ios,stripe/stripe-ios,NewAmsterdamLabs/stripe-ios,stripe/stripe-ios,fbernardo/stripe-ios,fbernardo/stripe-ios,NewAmsterdamLabs/stripe-ios,NewAmsterdamLabs/stripe-ios,stripe/stripe-ios,NewAmsterdamLabs/stripe-ios,fbernardo/stripe-ios